WASM error handling in SubtleCrypto through web worker

[AaronRobinsonMSFT]

The work to enable WASM to use SubtleCrypto, #65966, had some follow ups on how to handle error cases. Specifically, the communication channel with the web worker could be hardened to convey more errors/failures. This could be accomplished through throwing an exception or the web worker communicating a failure case explicitly.

Source hints:

• crypto-worker.ts
  • see read_response and consider throwing an error.
• dotnet-crypto-worker.js
  • The reading in of a request could be including in the try/catch in await_request.
  • The await_request function could return a bespoke "error occurred" message instead of an exception string.

See #69741

/cc @radical @ericstj @layomia

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Issue Details

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The work to enable WASM to use SubtleCrypto, #65966, had some follow ups on how to handle error cases. Specifically, the communication channel with the web worker could be hardened to convey more errors/failures. This could be accomplished through throwing an exception or the web worker communicating a failure case explicitly.

Source hints:

• crypto-worker.ts
  • see read_response and consider throwing an error.
• dotnet-crypto-worker.js
  • The reading in of a request could be including in the try/catch in await_request.
  • The await_request function could return a bespoke "error occurred" message instead of an exception string.

/cc @radical @ericstj @layomia

Author:	AaronRobinsonMSFT
Assignees:	-
Labels:	arch-wasm, area-System.Security
Milestone:	7.0.0

[radical]

Another suggestion would be for the tests to confirm when running on browser that it did actually use the worker implementation.

[AaronRobinsonMSFT]

Another suggestion would be for the tests to confirm when running on browser that it did actually use the worker implementation.

I think this is being done. See src/tests/BuildWasmApps/Wasm.Build.Tests/NativeLibraryTests.cs. There is a check for console output. I commented on this in the JavaScript file.

[radical]

I think this is being done. See src/tests/BuildWasmApps/Wasm.Build.Tests/NativeLibraryTests.cs. There is a check for console output. I commented on this in the JavaScript file.

Yes, but the xharness webserver is setup in two different places for Wasm.Build.Tests, and the library tests. I was just suggesting that we add some kinda confirmation for the library tests also, so it doesn't accidentally start using the fallback, and we don't find out.

[eerhardt]

Note: when fixing this, we also need to ensure that the "lock" added in #70185 is cleared on error.